ES5写法

  1.     Function.prototype._bind = function () {
  2.       if (typeof this !== "function") {
  3.         throw new TypeError('Error')
  4.       }
  5.       let self = this
  6.       let args = Array.prototype.slice.call(arguments, 1) //取出除第一个参数的所有参数
  7.       let _this = arguments[0]
  8.       return function () {
  9.         return self.apply(_this, args)
  10.       }
  11.     }
  13.     function fn() {
  14.       this.a = arguments[0]
  15.       console.log('a:' + this.a);
  16.       console.log('name:' + this.name);
  17.     }
  18.     let obj = {
  19.       name: 'zs'
  20.     }
  21.     console.log(fn._bind(obj, ['apply', '0', '1'])(1, 3));

ES6写法

  1.  // ES6写法
  2.     Function.prototype._bind = function (...args) {
  3.       if (typeof this !== "function") {
  4.         throw new TypeError('Error')
  5.       }
  6.       let self = this
  7.       let context = args.shift()  //shift 方法是将数组中的第一个数删除，然后然后返回删除的数
  8.       return function (...arg) {
  9.         console.log(args[0].concat([...arg]));
  10.         return self.apply(context, args[0].concat([...arg]))
  11.       }
  12.     }
  14.     function fn() {
  15.       this.a = arguments[0]
  16.       console.log('a:' + this.a);
  17.       console.log('name:' + this.name);
  18.     }
  19.     let obj = {
  20.       name: 'zs'
  21.     }
  22.     console.log(fn._bind(obj, ['apply', '0', '1'])(1, 3));